1. Technical Field
The present invention relates to apparatus for analyzing biologic fluid samples in general, and to containers for holding a biologic fluid sample during analytical procedures in particular.
2. Background Information
Most analytical methods for evaluating constituents within a biologic fluid sample require that the sample be substantially diluted prior to evaluation. A typical chemical analysis, for example, involves placing a substantially diluted sample into a transparent cuvette of known dimensions and constant light path for evaluation. The cuvette can be made from glass or a hard acrylic that is ground or otherwise manufactured to tight tolerances. The tight tolerances, which are necessary to insure the accuracy of the light path through the cuvette, also make the cuvette undesirably expensive. In hematological analyses, a substantially diluted sample is typically passed through a flow cell within an optical flow cytometer or through an impedance orifice in an impedance type flow cytometer. Most flow cytometers require mechanical subsystems to dilute the sample, to control the sample flow rate through the flow cell, and multiple sensors to evaluate the diluted sample. A special problem associated with hematology measurements is the wide dynamic range of particles that must be enumerated. The red blood cells (RBC""s) are the most numerous at about 4.5xc3x97106 RBC""s per microliter (xcexcl), followed by the platelets at about 0.25xc3x97106 platelets per xcexcl, and the white blood cells (WBC""s) at about 0.05xc3x97106 per xcexcl. Since all cells or particles must be enumerated during a full analysis, the range of cells/particles necessitates at least two dilution levels. The ability to perform multiple dilutions undesirably adds to the complexity of the machine. A person of skill in the art will recognize disadvantages associated with flow cytometers including plumbing leaks and inaccuracies due to fluid control miscalibration. In both of the aforementioned analyses, the operator (or the apparatus itself) must purge the biologic fluid sample from the apparatus and thoroughly clean the apparatus to avoid contaminating subsequent analyses. The substantial dilution required in both analyses also increases the likelihood of error, the complexity of the analysis, and the per analysis cost.
Other analytical methods minimize the above described problems by employing a disposable sample analytical chamber. In one chemical analytical method, the biologic fluid sample is placed in a flexible sealed pouch where it remains during the analysis. This approach avoids the need for plumbing, flow controls, and cleaning the container, but requires a large diluent volume and is restricted to standard measurements of light transmission. In the above method, the light path dimensions are controlled by the analytical instrument, which forms the flexible pouch into a cuvette of the desired thickness at the time of measurement. Other, similar xe2x80x9cwet chemicalxe2x80x9d, systems employ a rigid analytical cuvette of specifically manufactured thickness. Other methods for performing a chemical analysis on a biologic fluid sample employ single or multiple test film substrates. The test film substrates also avoid the problems associated with dilution, flow controls, etc., but still require precise sample measurement and placement and are also limited to those analyses that employ light reflectance. The test film substrate methods are further limited by requiring that the associated disposable always have identically located analytical regions; if the desired information is not present in the predetermined analytical areas, then the test film substrate will not yield useful information. Hematological analytical methods which employ a disposable sample analytical chamber include the HemaCue(trademark) and the QBC(trademark). The HemaCue(trademark) system is a method for measuring hemoglobin using a small cuvette. The HemaCue(trademark) method is particularly useful for its intended purpose, but it is unable to measure particulate constituents of whole blood. The QBC(trademark) system, a registered trademark of Becton Dickinson and Company of Franklin Lakes, N.J., USA involves placing a hematological fluid sample within a cylindrical tube and centrifuging the tube and sample for a given period of time. The centrifuge process separates fluid sample constituents into layers according to their density. A float disposed within the tube facilitates evaluation of constituents within each layer. Specific hematological tests may be performed in a disposable test system employing a scannable optical window in a device produced by Biometric Imaging. In this device, a substantially undiluted sample of whole blood is placed into a capillary of known and constant dimension where it is subjected to a laser scan which identifies some sub-types of WBC""s. The Biometric Imaging method is also limited in that it is unable to measure any other constituents of whole blood.
Serologic or immunologic analyses measure soluble substances in blood, usually proteins such as specific immunoglobulins. These tests are often performed by admixing the sample with a sensitized particulate, such as latex, which will agglutinate in the presence of the protein of interest. Another method for performing a more quantitative immunological analysis is to use enzymatically linked color changes, such as ELISA. All of these methods are performed on apparatus specialized for their use.
Another common specialized test is urinalysis. The analysis of urine is generally divided into two separate phases: the determination of the bulk and/or chemical properties of the sample and the analysis of particulates within the sample. These analyses require distinctly different disciplines and are usually done separately. There are large and complicated machines that can perform both types of analyses, but they are extremely expensive and require moderate maintenance and operator skill.
None of the above described analytical methods is capable of performing hematological, chemical/immunochemical, and serologic analyses on sample constituents within the same instrument. As a result, it has been necessary to purchase apparatus devoted to performing chemical analyses and apparatus devoted to performing hematological analyses. It has also been necessary to train technicians to operate the various types of apparatus, and to provide laboratory space and maintenance for them. It has also been impossible to combine hematological and chemical analyses in the same apparatus for those analyses where it would be advantageous to combine the analyses. In an analysis to determine anemia, for example, it is preferable to perform both hematological analyses (e.g., hemoglobin, hematocrit, and reticulocyte count) and chemical or immunochemical analyses (e.g., iron or ferritin, and/or vitamin B12 or folate determinations) on the sample. None of the above described methods permit hematological and chemical analyses on a single sample of blood in a single disposable sample chamber. As a result, the laboratory technician must separate and transport the various samples to their separate instruments which are often in separate laboratories, thereby increasing the inefficiency of the process as well as the potential for loss or misidentification of the sample. Also, the results of the analyses may not be available at the same time which increases the difficulty of interpreting the analysis results.
What is needed is a single container for holding a biologic fluid sample that can be used for multiple analyses including but not limited to hematological, chemical, immunological, serological, and urine analyses, one in which multiple analyses can be performed on the same sample in one instrument which presents a common operator interface, one that is operable with substantially undiluted biologic fluid samples, one whose method of sample introduction into the container is similar for each set of analyses, and one that can be used effectively as a disposable.
It is, therefore, an object of the present invention to provide a container for holding a biologic fluid sample which permits analysis of multiple constituents within the same sample, and in particular analysis of constituents residing individually or in groups, using quantitative image analysis.
It is another object of the present invention to provide a container for holding a biologic fluid sample for analysis which is operable for analyses which require information related to the bulk and/or chemical properties of the sample and those which require information related to the particulates content of the sample.
It is another object of the present invention to provide a container for holding a biologic fluid for analysis which is operable in multiple analytical disciplines including but not limited to hematology, chemical/immunochemical, serology/immunological, and urinalysis.
It is another object of the present invention to provide a container which can include analytical chambers of varying dimensions whose thickness can be correlated to a spatial coordinate in order to encompass a wide dynamic range of contained particulates.
It is another object of the present invention to provide a container for holding a biologic fluid sample that requires only a single instrument to sense for information within the sample or associated with the container and interpret the sensed information for use in multiple analyses, thereby decreasing the training and quality control requirements of the laboratory.
It is another object of the present invention to provide a container for holding a biologic fluid sample for analysis that can be used effectively as a disposable.
It is another object of the present invention to provide a container for holding a biologic fluid sample for analysis that does not require substantial dilution of the sample before analysis.
It is another object of the present invention to provide a container for holding a biologic fluid sample which is operable with minimal quantities of blood or other biologic fluid.
It is another object of the present invention to provide a container for holding a biologic fluid sample that facilitates safe handling of the biologic fluid sample for the test operator.
It is another object of the present invention to provide a container for holding a biologic fluid sample that includes an analytical area suitable for imaging by a digital camera or other digital imaging device/image dissector which produces output suitable for quantitative analysis.
It is another object of the present invention to provide a container for holding a biologic fluid sample that has the capability of retaining an untreated or a substantially undiluted sample prior to analysis and releasing said sample into the analytical region when needed.
It is another object of the present invention to provide a container for holding a biologic fluid sample that carries indicia which provides information to the instrument of use in performing the analysis(es) at hand.
According to the present invention, a container for holding a biologic fluid sample for analysis is provided which includes a chamber and a label. The chamber includes a first wall, a transparent second wall, and at least one feature located at a known spatial location within the chamber. The transparent second wall permits a fluid sample quiescently residing within the chamber to be imaged through the second wall. The at least one feature is operable to enable the analysis of the biologic fluid. The at least one feature may, for example, include a physical characteristic of the chamber, a geometric characteristic of, or within, the chamber, and/or a reagent. The label directly or indirectly contains information regarding the at least one feature, including the spatial location of the feature within the chamber. The sample is analyzed by an analytical device that utilizes the information communicated through the label.
The preferred analytical device for use with the present invention container is the subject of co-pending U.S. patent application Ser. No. 09/255,672. Briefly described, the xe2x80x9cApparatus for Analyzing Substantially Undiluted Samples of Biologic Fluidsxe2x80x9d as it is referred to, includes a Reader Module, a Transport Module, and a Programmable Analyzer. The Reader Module includes optics which are operable to image a field within the container, and apparatus to access information through the label attached to the container. The Transport Module includes apparatus for moving the container relative to the Reader Module, or vice versa. The Programmable Analyzer is programmed with instructions to coordinate the operation of the Reader Module and Transport Module according to a variety of analysis algorithms. Which analysis algorithms are used is typically determined by reading the container label.
An advantage of the present invention container is that it is operable for a variety of analyses including but not limited to hematological, chemical, immunochemical, serologic, urinalysis and immunological analyses. In addition, it is possible to perform a multitude of those analyses on the same sample, in the same analytical device. Some traditional analysis methods pass light into a cuvette, and interpret the light traversing through or emitting from the cuvette to provide analytical data. Other methods, such as those which utilize film substrates for analyzing sample constituents utilize light reflected from the film layer. The data available using these types of methods is relatively uniform and does not contain any spatial information. Thus, they are useful for analyzing bulk properties of the sample, meaning those properties that are distributed uniformly in solution or in suspension, but it is impossible to derive useful data about individual particulate materials within the sample. The absence of spatial information limits the number of tests possible on a given sample. If a sample is tested for optical density using the above described cuvette, for example, the test parameters will provide information about a particular constituent, but will not provide the information necessary to characterize cellular contents. The present invention container, in contrast, includes an analytical chamber (or chambers) which includes features that enable the Reader Module to extract both spatial information and quantitative photometric information from the sample quiescently residing within the chamber. The ability to analyze both types of information allows the combination of the instrument and the disposable to analyze a large number of different constituents, and consequently perform a far greater number of tests.
The ability of the present container to include one or more chambers operable for a variety of analyses enables the performance of a select battery of tests on a particular sample. A person of skill in the art will recognize that it is common to perform a battery of tests on a patient sample, and that there is great utility in being able to perform that battery on a single sample in a single analytical device. For example, when a patient""s blood sample is being analyzed to determine the hemoglobin concentration, it is usual to measure the hematocrit and white blood count and may be useful to enumerate the reticulocytes. Using the present invention, a chamber having the features of a known or determinable through-plane thickness and appropriate reagents would be used to measure the hemoglobin, and another chamber having the features of a dispersed colorant would be used to measure the hematocrit and white blood count. Another section of that chamber, or a separate chamber, would have the features of a colorant plus a region of very thin through-plane thickness where the reticulocytes would be enumerated. In the case of a battery of tests for the detection of a myocardial infarction, there could be a chamber having features operable to determine treponin and/or myoglobin, a chamber with features for determining potassium concentration, one that analyzed the creatinine phosphokinase levels, etc. An advantage of the present invention is that the chambers and features may be located anywhere within the confines of the container so long as the features are locatable by the analytical device, which allows for a test or series of tests to be designed using the best chamber and feature geometry for the particular analyses on a particular sample without being limited to a chamber region of a predetermined shape or size at a particular location.
The ability to perform different discipline analyses, for example hematological and chemical analyses, is significant for several reasons. First, the amount of equipment required to do the same number of analyses is reduced significantly. It follows that the cost of procuring and maintaining that equipment is similarly reduced. Also, the personnel training required to operate the equipment is reduced. Another reason is the versatility provided by a device that can perform different discipline analyses. Many clinical offices and laboratories are presently unable to justify the office space and expense associated with available test apparatus for each analytical discipline. With the versatile present invention, however, it will be possible to have greater in-house analytical ability because of the present invention""s relative minimal space requirements and low cost.
Another advantage of the present invention is that a disposable container for holding, analyzing, and disposing of a biologic fluid sample for analysis is provided. The present invention container is independent of the analytical device, inexpensive, readily loaded, and easily handled by an automated analytical device. The disposable container utilizes a standardized exterior configuration so that the analytical device can be set up for a standard container, regardless of the configuration of the chamber or chambers. In the example above where the container includes one or more chambers having features operable to enable a select battery of tests, the analytical device is set up to accept the standard container and the container label indicates directly or indirectly the tests to be perform and the feature or features within the chamber or chambers that enable those tests. These characteristics make the present container a desirable disposable. As a disposable, the present invention obviates the need to clean the sample chamber after each use and therefore the opportunity for contamination from the prior sample. The disposable nature of the present invention container also facilitates safe handling of the biologic fluid sample for the test operator by minimizing contact with all fluids.
Another advantage of the present invention container is that it uses a relatively small volume of biologic fluid rather than a large volume of significantly diluted biologic fluid. A person of skill in the art will readily recognize the advantages of avoiding the plumbing and fluid controls associated with most flow cytometers which require relatively large volume of diluted sample, as well as the advantages of avoiding the dilution steps, the dilution hardware, and the need for diluent.
Another advantage of the present invention is that it can hold an untreated or substantially undiluted sample prior to analysis and selectively release that sample into the analytical region when needed. As a result, those analyses which are time dependent can be performed using the present invention.